Is there anything other then the headlight on that same circuit? All of a sudden I started popping the 10A headlight fuse and haven't been able to track down the cause. I know the previous owner had added a driving light bar that I haven't tore into yet. I put probably 3500 miles on it since I purchased it with no electrical problems, but just started to pop this fuse. Any suggestions? Bike is a 2007 classic LT.

That's the strange thing it will be fine for a about a mile then cut out. I thought the lights were pulling too much power so threw a 15 in and same result I think the wiring developed a weak spot in the insulation somewhere and is shorting out... but didn't know if anyone had a similar problem. I don't think its a power demand problem because like I said it was fine for so long and just started popping recently

the first thing I would check is the PO's wiring work. In case there is a bare spot that is grounding when being shaken around. I do not know if anything else is on the same circuit as the headlight. But from my past experiences most of my wiring problems have been self induced (or human induced).

so I had a chance to check out the wiring today and wow... dude had bare wires hanging out all over the place, I thought for sure I found the problem. Well fired her up and let it idle for a bit and sure enough everything goes black. I guess I will have to keep looking tomorrow. I did however notice the lack of a relay so far. Now I know there absolutely should be one there and intend to install one if I dont find one in there somewhere, but now Im completely confused. if there was no relay all along why was there no issue from the start? Why all of a sudden are the lights pulling enough power to pop the fuse when I didnt have a problem for the previous 4000 miles?

Usually a relay is there to protect the initial supply switch from too much current arcing as it closes. The initial switch only has to deal with the lower current to supply the relay coil, and then the activated coil pulls a heavier duty contact (switch) together to handle the heavier current of the end load (in this case the headlight).

If you have no relay, your intial switch could be burning out or has arcing damage causing a voltage drop across itself and since it is in series with the rest of the circuit thereby increasing overall circuit amperage. Check your switch that feeds the circuit for such damage.

Your really need a schematic to sort this out, it will give the color and trace of everything, otherwise it's a nightmare physically tracing each wire to it's end. On my 2011 Nomad schematic a wire coming from the ignition switch feeds thru the fuse and then to the headlight relay. If you can find where the relay "used" to be, then trace that wire back to the fuse. Is that the fuse that's blowing ?

Additionally I surmise someone has bypassed the relay with this fused feeder wire and hooked it straight into the line feeding the HI/LO switch (which normally comes out of the relay). Both the ignition switch and the HI/LO switch could suffer arcing damage without the relay in place.

A test on each switch with an volt meter "should" show the same volts leaving the switches as what's going in them. Otherwise the switches have damage and are dropping volts and building series current amps. I don't get online as much as I used to so I may not get back to this thread for awhile. But the other guys can help you along after you test both these switches.

There also as said the possibility that the wiring has been foobarred, but with the relay "gone" I would first check those switches for damage.

Sounds like you have a short in the wiring and it's blowing fuses. If you blow a 15 amp fuse after putting one in then you definitely have a short. Don't leave a 15 amp fuse on the headlight circuit because the headlight wires are not heavy enough and it needs only a 10 amp fuse maximum. Some wire might have been rubbed bare and is shorting out.

Well the lights are after market it looks like he wired the to grab power from the headlight low beam power wire without adding a relay. So the stock 10A headlight circuit was now being loaded with the stock headlight and these after market lights. I'm going to wire the lights to their own circuit with a relay triggered by the running lights so they are always on regardless of hi/low beam.my past experience tells me this has to be the problem, once I cut the power to the aftermatket lights all together the fuse didn't pop at all after a good 25 minute test period.

I installed a radio shack single throw toggle switch on left side cover to operate on/off separately the front spot lights, and installed a relay inside that cover, getting the hot feed for the relay from the red wire under the seat for rear tail light, that red tail light wire gets hot when ignition key is turned on, when i turn off the ignition key the spot lights go off or I can turn the spots off at the side toggle switch. I drilled a small pilot hole in the plastic side cover then I used a 1 inch carpenters wood drill bit for the toggle switch hole. Measure twice and then drill once. You can use 22 gauge wire from that hot lead to the relay, and from battery to relay to spots I used 16 gauge wire, but 18 gauge there would also be fine.